[chromeos] New PowerManagerClient observer to collect power data.

chromeos/power/power_data_collector.h

Index: chromeos/power/power_data_collector.h
diff --git a/chromeos/power/power_data_collector.h b/chromeos/power/power_data_collector.h
new file mode 100644
index 0000000000000000000000000000000000000000..6c1c1f27ba479b6161e9dced9bc9320a03e94a64
--- /dev/null
+++ b/chromeos/power/power_data_collector.h
@@ -0,0 +1,82 @@
+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROMEOS_POWER_POWER_DATA_COLLECTOR_H_
+#define CHROMEOS_POWER_POWER_DATA_COLLECTOR_H_
+
+#include <vector>
+
+#include "base/gtest_prod_util.h"
+#include "base/time/time.h"
+#include "chromeos/dbus/power_manager_client.h"
+
+namespace power_manager {
+class PowerSupplyProperties;
+}
+
+namespace chromeos {
+
+// A class which starts collecting power metrics, like the battery charge, as
+// soon as it is initialized via Initialize().
+//
+// This class is implemented as a global singleton, initialized after
+// DBusThreadManager which it depends on.
+class PowerDataCollector
+    : public PowerManagerClient::Observer {

[Daniel Erat, 2013/12/12 01:31:52]

nit: just move this up to the end of the previous line

[Siva Chandra, 2013/12/13 22:10:39]

Done.

+ public:
+  struct PowerSupplySnapshot {
+    PowerSupplySnapshot();
+
+    // Time the snapshot was captured.
+    base::TimeTicks time;
+
+    // True if connected to external power at the time of the snapshot.
+    bool external_power;
+
+    // The battery charge as a percentage of full charge in range [0.0, 100.00].
+    double battery_charge;

[Daniel Erat, 2013/12/12 01:31:52]

nit: rename this to |battery_percent| as in PowerSupplyProperties to make it
obvious that it's a percentage and not actually the charge (i.e. Ah)

[Siva Chandra, 2013/12/13 22:10:39]

Done.

+  };
+
+ public:

[Daniel Erat, 2013/12/12 01:31:52]

nit: remove this; there's already a public access label earlier

[Siva Chandra, 2013/12/13 22:10:39]

Done.

+  // Can be called only after DBusThreadManager is initialized.
+  static void Initialize();
+
+  // Can be called only if initialized via Initialize, and before
+  // DBusThreadManager is destroyed.
+  static void Shutdown();
+
+  // Returns the global instance of PowerDataCollector.
+  static PowerDataCollector* Get();
+
+  // Returns a reference to a vector of power supply data.

[Daniel Erat, 2013/12/12 01:31:52]

nit: remove unnecessary comment. accessors also usually appear near the top of
the section, immediately after the c'tor and d'tor. since this class's c'tor and
d'tor are private, i'd put it between the PowerSupplySnapshot definition and
Initialize()

[Siva Chandra, 2013/12/13 22:10:39]

Done.

+  const std::vector<PowerSupplySnapshot>& power_supply_data(void) const {

[Daniel Erat, 2013/12/12 01:31:52]

remove void argument

[Siva Chandra, 2013/12/13 22:10:39]

Done.

+    return power_supply_data_;
+  }
+
+ private:
+  friend class base::RefCountedThreadSafe<PowerDataCollector>;

[Daniel Erat, 2013/12/12 01:31:52]

remove this

[Siva Chandra, 2013/12/13 22:10:39]

Done.

+  friend class PowerDataCollectorTest;
+  FRIEND_TEST_ALL_PREFIXES(PowerDataCollectorTest, PowerChanged);
+
+  explicit PowerDataCollector();

[Daniel Erat, 2013/12/12 01:31:52]

remove 'explicit'

[Siva Chandra, 2013/12/13 22:10:39]

Done.

+
+  virtual ~PowerDataCollector();
+
+  // Used in tests. Initializes the PowerDataCollector so that unit tests
+  // can be performed without depending on the DBusThreadManager.
+  static void InitializeTesting();

[Daniel Erat, 2013/12/12 01:31:52]

nit: remove this

[Siva Chandra, 2013/12/13 22:10:39]

Done.

+
+  // PowerManagerClient::Observer implementation:
+  virtual void PowerChanged(
+      const power_manager::PowerSupplyProperties& prop) OVERRIDE;

[Daniel Erat, 2013/12/12 01:31:52]

probably safest to include base/compiler_specific.h as well (that's where
OVERRIDE is defined, iirc)

[Siva Chandra, 2013/12/13 22:10:39]

Done.

+
+ private:
+  std::vector<PowerSupplySnapshot> power_supply_data_;
+
+  DISALLOW_COPY_AND_ASSIGN(PowerDataCollector);

[Daniel Erat, 2013/12/12 01:31:52]

i'd include base/basictypes.h as well for this macro

[Siva Chandra, 2013/12/13 22:10:39]

Done.

[Siva Chandra, 2013/12/13 22:10:39]

Done.

+};
+
+}  // namespace chromeos
+
+#endif  // CHROMEOS_POWER_POWER_DATA_COLLECTOR_H_